In manufacturing fields of manufacturing medical or pharmaceutical products or foods or in medical fields such as a surgical room, it is important to maintain a sterile state in the room. In particular, in decontamination of the sterile room that is a working room intended to manufacture medical or pharmaceutical products, there is a need to complete advanced decontamination validation which conforms to the GMP (Good Manufacturing Practice).
In recent years, for the purpose of decontamination of a working room such as a sterile room (hereinafter, referred to as a “room targeted to be decontaminated”), hydrogen peroxide gas is employed in place of formalin gas which is harmful for a human body. This hydrogen peroxide gas has a strong sterile effect and is inexpensive and easily available, and eventually, is effective as an environmentally acceptable decontamination gas to decompose into oxygen and water. However, the hydrogen peroxide gas has been conventionally available for use in decontamination of a small space such as an isolator or a glove box. On the other hand, there has been a problem that, in order to employ the hydrogen peroxide gas for decontamination, in a large space such as the room targeted to be decontaminated, a large amount of the hydrogen peroxide gas of a predetermined concentration must be stably supplied.
Therefore, in Patent Literature 1 given below, there is proposed a sterile liquefying apparatus as a decontamination gas generator in which concentration control of sterile gas (hydrogen peroxide gas) is easy, and moreover, a large amount of sterile gas (hydrogen peroxide gas) can be supplied. This sterile liquefying apparatus is intended to evaporate hydrogen peroxide water in air which has been heated to a high temperature by heating means to thereby generate hydrogen peroxide gas, and is provided with two temperature sensors at a downstream side of evaporating means. Due to a temperature difference between these temperature sensors, heating means is controlled, and the hydrogen peroxide gas concentration is stabilized.